Process for the production of liquid crystal display

Abstract

A process for the production of a liquid crystal display device having a color filter comprising: providing an assembly comprising, in order, a first support member, a plurality of first electrodes secured to the first support member, a liquid crystal layer, at least one second electrode and a second, substantially transparent support member, the assembly further comprising an imageable layer which, upon exposure to actinic radiation, can form three different colors, this imageable layer being disposed between the first and second support members; and exposing the assembly to actinic radiation so as to produce in the imageable layer a plurality of filter elements of first, second and third colors, said filter elements being aligned with the first electrodes, thereby forming a color filter lying between the first and second support members.

I claim: 
     
       1. A process for the production of a liquid crystal display device having a color filter, the process comprising: providing an assembly comprising, in order, a first support member, a plurality of first electrodes secured to the first support member, a liquid crystal layer, at least one second electrode and a second, substantially transparent support member, the assembly further comprising an imageable layer which, upon exposure to actinic radiation, can form three different colors, this imageable layer being disposed between the first and second support members; and   exposing the assembly to actinic radiation so as to produce in the imageable layer a plurality of filter elements of first, second and third colors, said filter elements being aligned with the first electrodes, thereby forming a color filter lying between the first and second support members.   
     
     
       2. A process according to claim 1 wherein a repeating feature of the first electrodes is detected, and the exposure to actinic radiation is controlled so that the filter elements are formed in registration with the repeating feature. 
     
     
       3. A process according to claim 1 wherein the first support member comprises a sheet of non-planarized glass and the second support member comprises a sheet of plastic. 
     
     
       4. A process according to claim 3 further comprising a polarizing layer disposed between the second support member and the second electrode. 
     
     
       5. A process according to claim 4 wherein the polarizing layer is a linear dichroic polarizing layer comprising a stretched poly(vinyl alcohol) sheet containing polyvinylene light-polarizing species. 
     
     
       6. A process according to claim 5 wherein the polarizing layer is a silylated poly(vinyl alcohol) sheet stabilized by organosilylation treatment against humidity and heat. 
     
     
       7. A process according to claim 1 wherein the second electrode comprises a sandwich of silver between layers of titanium dioxide, or a sandwich of gold and silver layers between layers of titanium dioxide. 
     
     
       8. A process for the production of a liquid crystal display device having a color filter, the process comprising: providing an assembly comprising, in order, a first support member, a plurality of first electrodes secured to the first support member, a liquid crystal layer, at least one second electrode and a second, substantially transparent support member, the assembly further comprising an imageable layer which, upon exposure to actinic radiation, can form three different colors, this imageable layer being disposed between the first and second support members; and   exposing the assembly to actinic radiation so as to produce in the imageable layer a plurality of filter elements of first, second and third colors, said filter elements being aligned with the first electrodes, thereby forming a color filter lying between the first and second support members,   wherein at least some of the filter elements are formed by applying a potential difference between some of the first electrodes and the second electrode while not applying a potential difference between others of the first electrodes and the second electrode, so that some parts of the liquid crystal layer are rendered substantially non-transmissive of radiation while other parts of the liquid crystal layer are rendered transmissive of radiation, and passing the actinic radiation through the liquid crystal layer, so that exposure of the imageable layer only occurs in parts of the imageable layer adjacent the transmissive parts of the liquid crystal layer.   
     
     
       9. A process according to claim 8 wherein the imageable layer is disposed between the second support member and the liquid crystal layer. 
     
     
       10. A process according to claim 9 wherein the first electrodes are divided into first, second and third sets, and wherein filter elements of the three different colors are formed in alignment with the first, second and third sets of the first electrodes by: applying a potential difference between the second and third sets of first electrodes and the second electrode, thereby rendering the liquid crystal adjacent the second and third sets of first electrodes substantially non-transmissive of radiation;   passing actinic radiation through the first support and the liquid crystal layer, thereby permitting the actinic radiation to pass through the liquid crystal adjacent the first set of first electrodes but not through the liquid crystal adjacent the second and third sets thereof, and thereby effecting an imagewise change in the portions of the imageable layer aligned with the first set of first electrodes;   thereafter, applying a potential difference between the first and third sets of first electrodes and the second electrode, thereby rendering the liquid crystal adjacent the first and third sets of first electrodes substantially non-transmissive of radiation;   passing actinic radiation through the first support and the liquid crystal layer, thereby permitting the actinic radiation to pass through the liquid crystal adjacent the second set of first electrodes but not through the liquid crystal adjacent the first and third sets of first electrodes, and thereby effecting an imagewise change in the portions of the imageable layer aligned with the second set of first electrodes;   thereafter, applying a potential difference between the first and second sets of first electrodes and the second electrode, thereby rendering the liquid crystal adjacent the first and second sets of first electrodes substantially non-transmissive of radiation; and   passing actinic radiation through the first support and the liquid crystal layer, thereby permitting the actinic radiation to pass through the liquid crystal adjacent the third set of first electrodes but not through the liquid crystal adjacent the first and second sets of first electrodes, and thereby effecting an imagewise change in the portions of the imageable layer aligned with the third set of first electrodes.   
     
     
       11. A process according to claim 8 wherein the passage of the actinic radiation through the liquid crystal layer is effected by moving at least one spot of actinic radiation across the imageable layer to form the filter elements while the position of the spot of radiation is controlled relative to the pattern in the liquid crystal layer. 
     
     
       12. A process according to claim 8 wherein the color-forming composition comprises a radiation absorber capable of absorbing actinic radiation and a leuco dye that, upon absorption of radiation by the radiation absorber, forms the colored material. 
     
     
       13. A process according to claim 12 wherein, upon absorption of the actinic radiation, the radiation absorber generates heat within the imageable layer, and the leuco dye undergoes a thermal reaction to form the colored material. 
     
     
       14. A process according to claim 13 wherein the leuco dye comprises any one of: a. an organic compound capable of undergoing, upon heating, an irreversible unimolecular fragmentation of at least one thermally unstable carbamate moiety, this organic compound initially absorbing radiation in the visible or the non-visible region of the electromagnetic spectrum, the unimolecular fragmentation visibly changing the appearance of the organic compound;   b. a substantially colorless di- or triarylmethane imaging compound possessing within its di- or triarylmethane structure an aryl group substituted in the ortho position to the meso carbon atom with a moiety ring-closed on the meso carbon atom to form a 5- or 6-membered ring, the moiety possessing a nitrogen atom bonded directly to the meso carbon atom and the nitrogen atom being bound to a group with a masked acyl substituent that undergoes fragmentation upon heating to liberate the acyl group for effecting intramolecular acylation of the nitrogen atom to form a new group in the ortho position that cannot bond to the meso carbon atom, whereby the di- or triarylmethane compound is rendered colored;   c. a colored di- or triarylmethane imaging compound possessing within its di- or triarylmethane structure an aryl group substituted in the ortho position to the meso carbon atom with a thermally unstable urea moiety, the urea moiety undergoing a unimolecular fragmentation reaction upon heating to provide a new group in the ortho position that bonds to the meso carbon atom to form a ring having 5 or 6 members, whereby the di- or triarylmethane compound becomes ring-closed and rendered colorless;   d. in combination, a substantially colorless di- or triarylmethane compound possessing on the meso carbon atom within its di- or triarylmethane structure an aryl group substituted in the ortho position with a nucleophilic moiety which is ring-closed on the meso carbon atom, and an electrophilic reagent which upon heating and contacting the di- or triarylmethane compound undergoes a bimolecular nucleophilic substitution reaction with the nucleophilic moiety to form a colored, ring-opened di- or triarylmethane compound;   e. a compound of the formula ##STR12## wherein M' has the formula: ##STR13## wherein R is alkyl; --SO 2  R 1  wherein R 1  is alkyl; phenyl; naphthyl; or phenyl substituted with alkyl, alkoxy, halo, trifluoromethyl, cyano, nitro, carboxyl, --CONR 2  R 3  wherein R 2  and R 3  each are hydrogen or alkyl, --CO 2  R 4  wherein R 4  is alkyl or phenyl, --COR 5  wherein R 5  is amino, alkyl or phenyl, --NR 6  R 7  wherein R 6  and R 7  each are hydrogen or alkyl, --SO 2  NR 8  R 9  wherein R 8  and R 9  each are hydrogen, alkyl or benzyl; Z' has the formula: ##STR14## wherein R' is halomethyl or alkyl; X is --N═, --SO 2  -- or --CH 2  --; D taken with X and M' represents the radical of a color-shifted organic dye; q is 0 or 1; and p is a whole number of at least 1; Z' being removed from M' upon the application of heat to effect a visually discernible change in spectral absorption characteristics of the dye;   f. a substantially colorless di- or triarylmethane compound of the formula: ##STR15## wherein ring B represents a carbocyclic aryl ring or a heterocyclic aryl ring; C 1  represents the meso carbon atom of the di- or triarylmethane compound; X represents --C(═O)--; --SO 2  -- or --CH 2  -- and completes a moiety ring-closed on the meso carbon atom, the moiety including the nitrogen atom bonded directly to the meso carbon atom; Y represents --NH--C(═O)--L, wherein L is a leaving group that departs upon thermal fragmentation to unmask --N═C═O for effecting intramolecular acylation of the nitrogen atom to open the N-containing ring and form a new group in the ortho position of ring B that cannot bond to the meso carbon atom; E is hydrogen, an electron-donating group, an electron-withdrawing group or a group, either an electron-donating group or an electron-neutral group that undergoes fragmentation upon heating to liberate an electron-withdrawing group; s is 0 or 1; and Z and Z' taken individually represent the moieties to complete the auxochromic system of a diarylmethane or triarylmethane dye when the N-containing ring is open, and Z and Z' taken together represent the bridged moieties to complete the auxochromic system of a bridged triarylmethane dye when the N-containing ring is open;   g. a colorless precursor of a preformed image dye substituted with (a) at least one thermally removable protecting group that undergoes fragmentation from the precursor upon heating and (b) at least one leaving group that is irreversibly eliminated from the precursor upon heating, provided that neither the protecting group nor the leaving group is hydrogen, the protecting and leaving groups maintaining the precursor in its colorless form until heat is applied to effect removal of the protecting and leaving groups whereby the colorless precursor is converted to an image dye;   h. a mixed carbonate ester of a quinophthalone dye and a tertiary alkanol containing not more than about 9 carbon atoms;   i. a leuco dye represented by: ##STR16## wherein: E represents a thermally removable leaving group;   tM represents a thermally migratable acyl group;   Q, Q' and C taken together represent a dye-forming coupler moiety wherein C is the coupling carbon of the coupler moiety;   and, (Y) taken together with N represents an aromatic amino color developer,   one of Q, Q' and (Y) containing an atom selected from the atoms comprising Group 5A/Group 6A of the Periodic Table, the groups E and tM maintaining the leuco dye in a substantially colorless form until the application of heat causes the group E to be eliminated from the leuco dye and the group tM to migrate from the N atom to the Group 5A/Group 6A atom thereby forming a dye represented by: ##STR17## wherein the dotted lines indicate that the tM group is bonded to the Group 5A/Group 6A atom in one of Q, Q' and (Y).   
     
     
       15. A process according to claim 12 wherein, upon absorption of the actinic radiation, the radiation absorber generates acid within the imageable layer, and, upon exposure to this acid, the leuco dye forms the colored material. 
     
     
       16. A process according to claim 15 wherein the imageable layer further comprises a superacid precursor capable of being decomposed, by radiation of a wavelength shorter than that of the actinic radiation absorbed by the radiation absorber, to form a superacid, the superacid precursor, in the absence of the radiation absorber, not being decomposed by the actinic radiation absorbed by the radiation absorber but, in the presence of the radiation absorber and the actinic radiation absorbed by the radiation absorber, decomposing to form a protonated product derived from the radiation absorber, the color-forming composition further comprising a secondary acid generator capable of being thermally decomposed to form a second acid, the thermal decomposition of the secondary acid generator being catalyzed in the presence of the superacid derived from the superacid precursor, and the leuco dye undergoing a change to form the colored material in the presence of the second acid. 
     
     
       17. A process according to claim 16 wherein the radiation absorber has a unprotonated form and a protonated form, the protonated form having substantially greater substantial absorption in the first wavelength range than the unprotonated form. 
     
     
       18. A process according to claim 17 wherein the imageable layer comprises: a first acid-generating layer comprising a radiation absorber in its protonated form, a superacid precursor and a secondary acid generator;   a first color-change layer disposed adjacent the first acid-generating layer and comprising a base and a first leuco dye undergoing a change in its absorption of radiation upon contact with the secondary acid generated upon acid-catalyzed decomposition of the secondary acid generator in the first acid-generating layer;   a first acid-resistant interlayer superposed on the first acid-generating layer and the first color-change layer;   a second acid-generating layer disposed on the opposed side of the first acid-resistant interlayer from the first acid-generating layer and the first color-change layer, the second acid-generating layer comprising a radiation absorber in its unprotonated form, a superacid precursor and a secondary acid generator, the second acid-generating layer further comprising a first auxiliary sensitizer which renders the superacid precursor therein susceptible to decomposition by actinic radiation of a first wavelength in the second wavelength range, but not susceptible to decomposition by actinic radiation of a second wavelength in the second wavelength range;   a second color-change layer disposed adjacent the second acid-generating layer and on the opposed side of the first acid-resistant interlayer from the first acid- generating layer and the first color-change layer, the second color-change layer comprising a base and a second leuco dye undergoing a change in its absorption of radiation upon contact with the secondary acid generated upon acid-catalyzed decomposition of the secondary acid generator in the second acid-generating layer, the absorption change undergone by the second leuco dye being different from that undergone by the first leuco dye;   a second acid-resistant interlayer disposed on the opposed side of the second acid-generating layer and second color-change layer from the first acid-resistant interlayer;   a third acid-generating layer disposed on the opposed side of the second acid-resistant interlayer from the second acid-generating layer and second color-change layer, the third acid-generating layer comprising a radiation absorber in its unprotonated form, a superacid precursor and a secondary acid generator, the third acid-generating layer further comprising a second auxiliary sensitizer which renders the superacid precursor therein susceptible to decomposition by actinic radiation of the second wavelength in the second wavelength range, but not susceptible to decomposition by actinic radiation of the first wavelength in the second wavelength range; and   a third color-change layer disposed adjacent the third acid-generating layer and on the opposed side of the second acid-resistant interlayer from the second acid-generating layer and the second color-change layer, the third color-change layer comprising a base and a third leuco dye undergoing a change in its absorption of radiation upon contact with the secondary acid generated upon acid-catalyzed decomposition of the secondary acid generator in the third acid-generating layer, the absorption change undergone by the third leuco dye being different from those undergone by the first and second leuco dyes.   
     
     
       19. A process for the production of a liquid crystal display device having a color filter comprising a plurality of filter elements spaced from one another, the display device further comprising an essentially opaque grid covering the spaces between the spaced filter elements, the process comprising: providing an assembly comprising, in order, a first support member, a plurality of first electrodes secured to the first support member, a liquid crystal layer, at least one second electrode and a second, substantially transparent support member, the assembly further comprising the color filter disposed between the first and second support members and an imageable layer also disposed between the first and second support members, the imageable layer being capable of undergoing a change in opacity upon exposure to actinic radiation; and   exposing selected portions of the imageable layer to actinic radiation, thereby leaving portions of the imageable layer aligned with the spaces between the filter elements essentially opaque but the portions of the imageable layer aligned with the filter elements themselves essentially transparent, and thereby forming the grid.   
     
     
       20. A process according to claim 19 wherein the imageable layer is substantially transparent prior to exposure to the actinic radiation, and wherein the process comprises rendering the parts of the liquid crystal layer adjacent the filter elements substantially opaque to radiation, and passing actinic radiation through the liquid crystal layer, so that exposure of the imageable layer only occurs in parts of the imageable layer aligned with the spaces between the filter elements, thereby rendering these parts of the imageable layer substantially opaque and thereby forming the grid.